Recently, it has been found that wild elephants only sleep two hours per night. Wild elephants also live quite long, the median life span is 56 years. Now, 56 years lived with 2 hours sleep per day amounts to about 51 years spent being awake, while a human being who dies at the age of 80 who sleeps 8 hours a day will have spent about 53 years being awake (here we ignore the larger sleep requirement during infancy, taking that into account may put the elephants ahead of us).

So, we see that taking sleeping time into account greatly affects the comparison between waking lifespans of animals. The question is then what land mammal has the longest lifespan when subtracting sleeping time i.e only counting the waking hours. Some sea mammals like whales are known to live for a very long time, but that may be due to very peculiar features of such mammals who have adapted to living in the oceans.

  • $\begingroup$ You cannot calculate it so mechanically. If you read just the Wikipedia article en.wikipedia.org/wiki/Sleep_in_non-human_animals#Sleep_duration, you'll find that the type of the sleep differs a lot between animals, so you cannot get comparable data just by "subtracting sleeping time". When you sleep and when an elephant sleeps, it's not the same experience :) $\endgroup$ – Honza Zidek Jun 20 '18 at 8:37

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